We have continued observation of the 17,800 men in the Asbestos Workers Union on January 1st, 1967, currently determining the status of each individual as of January 1st, 1976. 1,483.38 deaths were expected, 2,003 were recorded. The principal source of excess deaths was found in the cancer category; 281.49 such deaths were expected and 867 were found. In addition, there were 141 deaths of asbestosis. 51 deaths of pleural mesothelioma were seen and 93 of peritoneal mesothelioma. 92.28 deaths of lung cancer were expected and 427 were observed. There were also excess numbers of deaths of cancer of the larynx, oro-pharynx and kidney. These data reflect experiences in 150,950 man-years of observation. A number of significant observations are currently appearing. First, we are confirming the initial observation concerning the marked effect of asbestos exposure increasing the lung cancer risk of cigarette smoking; and that neither peritoneal nor pleural mesothelioma are associated. We are finding, too, that the risk of death of asbestosis is almost double for cigarette smokers, presumably adding bronchitis and emphysema to the asbestos interstitial fibrosis. We have also been analyzing excess deaths and have found that these increase beginning at 15 years from onset, reaching the extraordinary level of 43.7% of all deaths 40-44 years from onset being "excess." We are also finding in a preliminary analysis, that cessation of cigarette smoking has an important effect in lowering the risk of death of lung cancer. 5-10 years after cessation of smoking, rates are approximately one third of those currently smoking. It is our intention to continue prospective surveillance of the remaining 15,797 workers alive on January 1st, 1976.